Transport stream generating apparatus, turbo packet demultiplexing apparatus, and methods thereof

ABSTRACT

A transport stream generating apparatus, a turbo packet demultiplexing apparatus, and methods thereof, the transport stream generating apparatus including: a Reed Solomon (RS) encoder to RS-encode turbo data, an interleaver to interleave the RS-encoded turbo data, a duplicator to add a parity insertion area to the interleaved turbo data, and a multiplexer to multiplex normal data and the turbo data processed by the duplicator to generate a transport stream. Accordingly, reception performance can be improved in an advanced vestigial sideband (AVSB) system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation application of U.S. patent application Ser. No.12/100,572, filed Apr. 10, 2008, which claims the benefit of U.S.Provisional Patent Application No. 60/911,165, filed on Apr. 11, 2007 inthe United States Patent and Trademark Office, and claims priority fromKorean Patent Application No. 10-2007-0120783, filed on Nov. 26, 2007 inthe Korean Intellectual Property Office, the disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Aspects of the present invention relate to a transport stream generatingapparatus, a turbo packet demultiplexing apparatus, and methods thereof,and, more particularly, to a transport stream generating apparatus and aturbo packet demultiplexing apparatus that include an interleaver of alarge size suitable for an advanced vestigial sideband (AVSB) system,and methods thereof.

2. Description of the Related Art

With recent development in electronics and communications technologies,a broadcasting system field introducing a digital technology and variouspublished standards for digital broadcasting has become prevalent. Morespecifically, the Advanced Television Systems Committee (ATSC) vestigialsideband (VSB) standard is used in the U.S. and the Digital VideoBroadcasting-Terrestrial (DVB-T) standard is used in Europe.

The ATSC VSB transmission system is based on a National TelevisionSystem Committee (NTSC) frequency band, facilitates communicationsbetween a transmitter and a receiver, and is economically efficient. TheATSC VSB transmission system uses a single carrier amplitude modulationVSB and can ensure transmission of high quality video, audio, andauxiliary data with a single 6 MHz bandwidth.

FIG. 1 is a block diagram illustrating a conventional digitalbroadcasting system according to the ATSC VSB standard. Referring toFIG. 1, a conventional digital broadcasting system includes a dualtransport stream generating apparatus 10, a transmitting apparatus 20,and a receiving apparatus 30.

The dual transport stream generating apparatus 10 receives normal dataand turbo data from an outside source, and multiplexes the normal dataand the turbo data to generate a dual transport stream. The dualtransport stream generating apparatus 10 includes an RS encoder 12, aduplicator 14, and a multiplexer 16. The RS encoder 12 performsReed-Solomon (RS) encoding with respect to the turbo data. Theduplicator 14 prepares a parity insertion area in the RS-encoded turbodata. The multiplexer 16 multiplexes the turbo data having the parityinsertion area and the normal data to generate the dual transportstream.

The transmitting apparatus 20 receives the dual transport stream fromthe dual transport stream generating apparatus 10 and up-converts thedual transport stream through processes such as randomizing, RSencoding, interleaving, and modulating. The receiving apparatus 30down-converts the dual transport stream and recovers an original signalthrough processes such as demodulating, equalizing, derandomizing, RSdecoding, and deinterleaving.

As described above, the conventional digital broadcasting systemgenerally includes the dual transport stream generating apparatus 10,the transmitting apparatus 20, and the receiving apparatus 30, and thedual transport stream generating apparatus 10 generally includes the RSencoder 12, the duplicator 14, and the multiplexer 16. However, in theconventional digital broadcasting system having the above structure, iffading occurs in a mobile channel environment, a good signal receptioncannot be obtained, and reception performance deteriorates as a result.

SUMMARY OF THE INVENTION

Aspects of the present invention provide a transport stream generatingapparatus and a turbo packet demultiplexing apparatus that include aninterleaver of a large size suitable for an advanced vestigial sideband(AVSB) system, and methods thereof.

According to an aspect of the present invention, there is provided atransport stream generating apparatus for a digital broadcasting system,the transport stream generating apparatus including: a Reed Solomon (RS)encoder to RS-encode turbo data; an interleaver to interleave theRS-encoded turbo data; a duplicator to add a parity insertion area tothe interleaved turbo data; and a multiplexer to multiplex normal dataand the turbo data processed by the duplicator to generate a transportstream.

According to another aspect of the present invention, the interleavermay adjust a memory size thereof according to a data transmission rate.

According to another aspect of the present invention, the interleavermay be a convolutional interleaver.

According to another aspect of the present invention, the interleavermay set a number of branches thereof and a memory size thereof tosatisfy:

B*(B−1)*M=N*a packet length,

where B is the number of branches, M is the memory size, and N is aninteger.

According to another aspect of the present invention, there is provideda method of generating a transport stream in a digital broadcastingsystem, the method including: RS-encoding turbo data; interleaving theRS-encoded turbo data; adding a parity insertion area to the interleavedturbo data; and multiplexing normal data and the turbo data that has theparity insertion area added thereto to generate a transport stream.

According to another aspect of the present invention, the interleavingmay adjust a memory size of an interleaver performing the interleavingaccording to a data transmission rate.

According to another aspect of the present invention, the interleavingmay use a convolutional interleaver.

According to another aspect of the present invention, the interleavingmay set a number of branches of the interleaver and a memory size of theinterleaver to satisfy:

B*(B−1)*M=N*a packet length,

where B is the number of branches, M is the memory size, and N is aninteger.

According to another aspect of the present invention, there is provideda turbo packet demultiplexing apparatus that receives a turbo packet ina digital broadcasting system, the turbo packet demultiplexing apparatusincluding: a turbo extractor to extract turbo data; a condenser toextract a data area from the extracted turbo data; a deinterleaver todeinterleave the extracted data area; and an RS decoder to RS-decode thedeinterleaved data area.

According to another aspect of the present invention, the deinterleavermay adjust a memory size thereof according to a data transmission rate.

According to another aspect of the present invention, the deinterleavermay be a convolutional deinterleaver.

According to another aspect of the present invention, there is provideda method of demultiplexing a turbo packet in a digital broadcastingsystem, the method including: extracting turbo data; extracting a dataarea from the extracted turbo data; deinterleaving the extracted dataarea; and RS-decoding the deinterleaved data area.

According to another aspect of the present invention, the deinterleavingmay adjust a memory size of a deinterleaver performing thedeinterleaving according to a data transmission rate.

According to another aspect of the present invention, the deinterleavingmay use a convolutional deinterleaver.

According to another aspect of the present invention, there is provideda transport stream generating apparatus that processes turbo data togenerate a transmission stream to be transmitted in a digitalbroadcasting system, the transport stream generating apparatusincluding: an interleaver to interleave the RS-encoded turbo data.

According to another aspect of the present invention, there is provideda turbo packet demultiplexing apparatus that receives and processes aturbo packet in a digital broadcasting system, the turbo packetdemultiplexing apparatus including: a deinterleaver to deinterleave theextracted data area.

According to another aspect of the present invention, there is provideda digital broadcasting system including: a transport stream generatingapparatus to generate a transport stream, the transport streamgenerating apparatus including: a Reed Solomon (RS) encoder to RS-encodeturbo data, an interleaver to interleave the RS-encoded turbo data, aduplicator to add a parity insertion area to the interleaved turbo data,and a multiplexer to multiplex normal data and the turbo data processedby the duplicator to generate the transport stream; and a turbo packetdemultiplexing apparatus to receive the transport stream and to processthe turbo data in the transport stream, the turbo packet demultiplexingapparatus including: a turbo extractor to extract the turbo data fromthe received transport stream, a condenser to extract a data area fromthe extracted turbo data, a deinterleaver to deinterleave the extracteddata area, and an RS decoder to RS-decode the deinterleaved data area.

According to another aspect of the present invention, there is provideda method of transmitting turbo data in a digital broadcasting system,the method including: Reed Solomon (RS)-encoding the turbo data;interleaving the RS-encoded turbo data; adding a parity insertion areato the interleaved turbo data; multiplexing normal data and the turbodata to which the parity insertion area is added to generate a transportstream and transmitting the transport stream; receiving the transportstream and extracting the turbo data therefrom; extracting a data areafrom the extracted turbo data; deinterleaving the extracted data area;and RS-decoding the deinterleaved data area.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram illustrating a conventional digitalbroadcasting system according to the ATSC VSB standard;

FIG. 2 is a block diagram illustrating a transport stream generatingapparatus according to an embodiment of the present invention;

FIG. 3 is a view illustrating the interleaver of FIG. 2;

FIG. 4 is a block diagram illustrating a transmitting apparatusaccording to an embodiment of the present invention;

FIG. 5 is a block diagram illustrating a receiving apparatus accordingto an embodiment of the present invention;

FIG. 6 is a block diagram illustrating a turbo packet demultiplexingapparatus according to an embodiment of the present invention;

FIG. 7 is a flowchart illustrating a method of generating a transportstream according to an embodiment of the present invention; and

FIG. 8 is a flowchart illustrating a method of demultiplexing a turbopacket according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

FIG. 2 is a block diagram illustrating a transport stream generatingapparatus 100 according to an embodiment of the present invention.Referring to FIG. 2, the transport stream generating apparatus 100includes a Reed Solomon (RS) encoder 110, an interleaver 120, aduplicator 130, and a multiplexer 140.

The RS encoder 110 RS encodes received turbo data. Specifically, the RSencoding calculates parity for the turbo data, and adds the parity tothe turbo data. The RS encoding may encode the turbo data with theexception of a synchronization signal of the turbo data. The interleaver120 interleaves the RS-encoded turbo data. The interleaver 120 adjusts amemory size according to a data rate, which will be described in detailbelow with reference to FIG. 3.

The duplicator 130 adds a parity insertion area to the turbo datainterleaved by the interleaver 120. The duplicator 130 converts eachbyte of a turbo stream according to a pre-set coding rate, therebypreparing a parity insertion area between data bits within the turbostream. The multiplexer 140 multiplexes normal data and the turbo dataprocessed by the duplicator 130, thereby generating a transport stream.The transport stream is then transmitted to a transmitting apparatus(not shown), which will be described below. The generated transportstream may be a dual transport stream, or a multi transport stream.

FIG. 3 is a view illustrating the interleaver 120 of FIG. 2. In general,188 byte packets are used as an input to the transport stream generatingapparatus 100 in the advanced vestigial sideband (AVSB) system. However,it is understood that aspects of the present invention are not limitedthereto. For example, 187 byte packets not including a synchronizationsignal byte may be used as an input to the transport stream generatingapparatus 100. N number of RS-encoded packets (where N is an integer)are inserted into one field, and accordingly, if a (207,187) RS encodingis performed for the 187 byte packets, bytes corresponding to N times207(9*23) bytes are inserted into one field. Also, the RS-encoded 207byte packet starts from a position of the field. In order to perform anRS decoding after deinterleaving, a receiving side determines the startposition of the RS-encoded 207 byte packet. For this, the RS-encodedpacket may start from the start position of the field.

In the AVSB system, the RS-encoded packet starts from the start positionof the field and the N number of packets are inserted in one field (Nbeing an integer). Accordingly, if the delay of the interleaver 120 isset to be N times the length of the RS-encoded 207 byte packet, thereceiving side can perform an RS decoding from the start position of thefield.

The interleaver 120 provided in the transport stream generatingapparatus 100 adjusts a memory size according to a data rate. Any typeof interleaver can be used for the interleaver 120. For example, aninterleaver having a long interleaving depth (such as a convolutionalinterleaver) for the purpose of improving reception performance evenunder fading conditions may be used. FIG. 3 illustrates a structure ofthe convolutional interleaver.

The delay of the convolutional interleaver after interleaving anddeinterleaving is expressed by the following Equation 1:

D=B*(B−1)*M,  Equation 1

where D denotes a delay, B denotes a number of branches, and M denotes amemory size.

If the delay D obtained by Equation 1 is set to be N times the length ofthe packet when the convolutional interleaver is designed, the receivingside can accurately know where an RS decoding is to be performed. As thenumber of branches B increases, performance improves, though it isdifficult to reach a maximum delay D. Accordingly, the number ofbranches B and the memory size M can be appropriately adjusted. Forexample, the convolutional interleaver of FIG. 3 has a number ofbranches (B) equal to 46, and a memory size (M) equal to 9. Also, indesigning the convolutional interleaver, the number of branches B is setto have a value by which a transmission data unit is dividable. Thetransmission data unit is a unit of normal data of VSB, and 52 segmentsor 1 field may be selected as a transmission data unit.

Additional coding or interleaving processes may be performed accordingto a transmission data unit. For example, if (207,187) RS-encoded 207byte packet data is to be processed in the unit of one field andtransmitted at 1.5 Mpbs, 24 packets can be transmitted per one field.The total number of bytes of 24 packets is 24.times.207 bytes, and thisvalue can be divided by the number of branches B. Accordingly, atransmitting side and a receiving side can start the convolutionalinterleaving and the convolutional deinterleaving from a branchcorresponding to a start position of the transmitted data.

The data passing through the convolutional interleaver in thetransmission data unit may contain an integer number of packets that hasundergone an additional encoding (such as an RS coding). In this case,if the convolutional interleaver starts from an uppermost position at astart position of the transmission data unit, the interleaver ends withthe last branch at an ending position of the transmission data unit.That is, the start position of every transmission data unit is connectedto the uppermost position of the convolutional interleaver. If thenumber of branches B is set to be a value by which the length of thepackets is divisible, the data can be received. Also, if the startposition of the transmission data unit is connected to the uppermostposition of the convolutional interleaver having a large memorycapacity, the data can be more easily received.

As described above, if the delay D is set to be N times the packetlength, the receiving side can accurately know the location of the RSdecoding. For example, if the number of branches is 46 (B=46) and thememory size is 9 (M=9) as shown in FIG. 3, a delay D corresponding to Ntimes the packet length is set in the receiving side afterRS-deinterleaving. In this example, since the delay is N times thepacket length when the receiver performs the deinterleaving, the branchis connected to the same position as the start position of thetransmission data unit, and the RS decoding is additionally performedwith respect to the output signal from the start position according tothe length of the received packets.

The AVSB system may support 375 Kbps, 500 Kbps, 750 Kbps, 1 Mbps, 1.5Mbps as a turbo data transmission mode in view of a data rate. However,it is understood that the transmission data rate mode is not limited tothe above and may be variable. The number of packets per one field inthe above-mentioned modes is 6, 8, 12, 16, and 24, respectively. Inorder to make delays caused by the interleaving in all modes equal,memory sizes may differ according to the transmission data sizes in therespective modes. For example, if the number of branches is 46 and therespective memory sizes are 9*3, 9*4, 9*6, 9*8, 9*12 (which areproportional values to the transmission rates), and if the delay isdivided by the number of bytes (207*6, 207*8, 207*12, 207*16, 207*24)existing in one field, a delay having the same size as the 45 fields(i.e., B-1 or 46-1) is generated.

The delays may be made to be equal in order to maintain a constantreception performance in several modes. As the delay values of theinterleaver 120 are made equal, it is possible to set the delay value tobe N times the 207 bytes of the RS-encoded packet and also to reach adesired value. In this case, the receiving side performs an RS decodingfrom the start position of the field, thereby obtaining turbo data.

If the interleaver 120 is designed to interleave (208,188) RS-encoded188 byte packet data, the memory size M is adjusted according to a datarate in order to make the delays of the data modes equal and/or thenumber of branches is set to be 52 in order to connect a start positionand an end position of the transmission unit to the first branch and thelast branch.

FIG. 4 is a block diagram illustrating a transmitting apparatus 200according to an embodiment of the present invention. Referring to FIG.4, the transmitting apparatus 200 includes a randomizer 210, a parityarea generator 220, a data interleaver 230, a turbo processor 240, adata deinterleaver 250, a parity area removal unit 260, and a modulator270. As described above, the transmitting apparatus 200 receives thetransport stream from the transport stream generating apparatus 100.

The randomizer 210 randomizes the transport stream received from thetransport stream generating apparatus 100. The parity area generator 220adds a parity area to the randomized transport stream. The datainterleaver 230 interleaves the transport stream having the parity areaadded thereto. The turbo processor 240 detects turbo data from theinterleaved transport stream and robustly processes the detected turbodata. The shown turbo processor 240 includes an N/T demultiplexer 241,an outer encoder 242, an outer interleaver 243, and an N/T multiplexer244. The N/T demultiplexer 241 divides the interleaved transport streaminto normal data and turbo data. The N/T demultiplexer 241 thentransmits the turbo data to the outer encoder 242 and the normal data tothe N/T multiplexer 244. That is, the N/T demultiplexer 241 transmitsthe transport stream from which the turbo data is separated to the N/Tmultiplexer 244. The outer encoder 242 encodes the turbo data divided bythe N/T demultiplexer 241. The outer interleaver 243 interleaves theencoded turbo data. The N/T multiplexer 244 inserts the turbo data thathas been processed by the outer encoder 242 and the outer interleaver243 into the transport stream from which the turbo data was separated,thereby remaking a transport stream in which only the turbo data isrobustly processed.

The data deinterleaver 250 deinterleaves the transport stream that isoutput from the turbo processor 240. The parity area removal unit 260removes the parity area from the deinterleaved transport stream. Themodulator 270 channel-modulates the transport stream, up-converts thetransport stream to an RF channel band signal, and transmits theup-converted transport stream. The transmitted transport stream may thenbe received by a receiving apparatus (not shown) through a channel.

It is understood that all aspects of the present invention are notlimited to the above construction of the transmitting apparatus 200. Forexample, according to other aspects, the transmitting apparatus 200 maynot include the randomizer 210, the parity area generator 220 and theparity area removal unit 260, and/or the data interleaver 230 and thedata deinterleaver 25 depending on circumstances. That is, thetransmitting apparatus 200 shown in FIG. 4 is merely an example of anapparatus for transmitting the transport stream generated by thetransport stream generating apparatus 100 according to an embodiment ofthe present invention, and is not limited to the structure as describedabove. It will be apparent to an ordinarily skilled person in the artthat various types of transmitting apparatuses can be applicable.

FIG. 5 is a block diagram illustrating a receiving apparatus 300according to an embodiment of the present invention. Referring to FIG.5, the receiving apparatus 300 includes a demodulator 301, an equalizer303, a Viterbi decoder 305, a multiplexer 307, a first datadeinterleaver 309, an RS decoder 311, a first derandomizer 313, a turbodecoder 315, a second data deinterleaver 317, a parity removal unit 319,a second derandomizer 321, and a turbo packet demultiplexer 323.

If a transport stream that has been modulated in the form of an RFsignal is received through a channel, the demodulator 301 detects asynchronization signal from a baseband signal of the received transportstream, and demodulates the transport stream. The equalizer 303equalizes the demodulated transport stream. Accordingly, it is possibleto compensate for channel distortion that is caused by a multipath ofthe channel. The Viterbi decoder 305 performs an error correction withrespect to normal data of the equalized transport stream and decodes anerror-corrected symbol, thereby outputting a symbol packet. Themultiplexer 307 serves as a switch for the normal data received from theViterbi decoder 305 or the turbo decoder 315. The first datadeinterleaver 309 deinterleaves the normal data. The RS decoder 311 RSdecodes the deinterleaved normal data. The first derandomizer 313derandomizes the RS-decoded normal data.

The turbo decoder 315 turbo decodes the turbo data from the transportstream. The second data deinterleaver 317 deinterleaves theturbo-decoded turbo data. The parity removal unit 319 removes parityfrom the deinterleaved turbo data. The second derandomizer 321derandomizes the turbo data from which the parity is removed. The turbopacket demultiplexer 323 processes the derandomized turbo data, whichwill be described below with reference to FIG. 6.

It is understood that all aspects of the present invention are notlimited to the above construction of the transmitting apparatus 200. Forexample, according to other aspects, the receiving apparatus 300 may notinclude the second data deinterleaver 317, the parity removal unit 319,and/or the second derandomizer 321 depending on circumstances. That is,the receiving apparatus 300 of FIG. 5 is merely an example of a receivercorresponding to the transmitting apparatus 200 of FIG. 4, and is notlimited to the structure as described above. As described above,modifications and variations can be applied to the transmittingapparatus 200 and, accordingly, the receiving apparatus 300 can bemodified and varied.

FIG. 6 is a block diagram illustrating a turbo packet demultiplexingapparatus 323 according to an embodiment of the present invention.Referring to FIG. 6, the turbo packet demultiplexing apparatus 323includes a turbo extractor 325, a condenser 327, a deinterleaver 329,and an RS decoder 311. The turbo extractor 325 extracts turbo data froma transport stream. However, if turbo data is directly input into theturbo packet demultiplexing apparatus 323, the turbo extractor 325 maynot be operated. The condenser 327 extracts a data area not including aparity area from the turbo data extracted by the turbo extractor 325.However, if the data area is input directly without the parity, thecondenser 327 may not be operated. The deinterleaver 329 deinterleavesthe data area extracted by the condenser 327. The deinterleaver 329 ofthe turbo packet demultiplexing apparatus 323 corresponds to theinterleaver 120 of the transport stream generating apparatus 100 of FIG.2. Like the interleaver 120, the deinterleaver 329 adjusts a memory sizeaccording to a data rate. If the interleaver 120 of the transport streamgenerating apparatus 100 is a convolutional interleaver, thedeinterleaver 329 employs a convolutional deinterleaver. Theconvolutional deinterleaver may be designed to be connected in a reverseway to the convolution interleaver. The RS decoder 311 RS decodes to thedata area of the deinterleaved turbo data.

FIG. 7 is a flowchart illustrating a method of generating a transportstream according to an embodiment of the present invention. Referring toFIG. 7, the turbo data is RS encoded in operation S400, and theRS-encoded turbo data is interleaved in operation S410. A convolutionalinterleaver may interleave the RS-encoded turbo data.

A parity insertion area is added to the interleaved turbo data inoperation S420, and normal data and the turbo data are multiplexed togenerate a transport steam in operation S430. The transport streamgenerated in operations S400 through S430 is transmitted to thetransmitting apparatus 200.

FIG. 8 is a flowchart illustrating a method of demultiplexing a turbopacket according to an embodiment of the present invention. Referring toFIG. 8, turbo data is extracted from a transport stream in operationS500. According to other aspects, the turbo data is directly input suchthat the method does not include an extracting operation.

A data area is extracted from the turbo data in operation S510, and theextracted data area is deinterleaved in operation S520. A convolutionaldeinterleaver may deinterleave the extracted data area. Thedeinterleaved turbo data is RS decoded and output in operation S530.

As described above, a transport stream generating apparatus 100according to aspects of the present invention performs an interleavingprocess (for example, using a convolutional interleaver) to generate atransport stream, and the transport stream is transmitted to a receivingapparatus 300 through a transmitting apparatus 200. The receivingapparatus 300 performs a deinterleaving process (for example, using aconvolutional deinterleaver) to recover an original broadcast signalfrom the received transport stream. Accordingly, reception performancein the AVSB system can be improved. The transport stream generatingapparatus, the turbo packet demultiplexing apparatus, and methodsthereof may use an interleaver of a large size suitable for an AVSBsystem, thereby improving a reception performance in the AVSB system.

While not required in all aspects, aspects of the present invention canbe implemented using software encoded on one or more computer-readablemedia for use with one or more computers and/or processors.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

What is claimed is:
 1. A digital broadcasting apparatus comprising: arandomizer to randomize a data; a parity area generator to generate aparity area for inserting a parity bit for the randomized data; adeinterleaver to deinterleaves the data which the parity area isgenerated; and a parity area eliminator to removes the parity area fromthe deinterleaved data.
 2. The digital broadcasting apparatus as claimedin claim 1, further comprising: a Reed Solomon (RS) encoder to RS-encodethe data; and an interleaver to interleave the RS-encoded additionaldata.
 3. The digital broadcasting apparatus as claimed in claim 2,wherein the interleaver adjusts a memory size thereof according to adata transmission rate.
 4. The digital broadcasting apparatus as claimedin claim 2, wherein the interleaver is a convolutional interleaver. 5.The digital broadcasting apparatus as claimed in claim 4, wherein anumber of branches of the convolutional interleaver is set to be aproper divisor of a transmission data unit of the digital broadcastingsystem.
 6. A data processing method comprising: randomizing a data;generating a parity area for inserting a parity bit for the randomizeddata; deinterleaving the data which the parity area is generated; andremoving the parity area from the deinterleaved data.
 7. The dataprocessing method as claimed in claim 6, further comprising: RS-encodingthe data; and interleaving the RS-encoded additional data.
 8. The dataprocessing method as claimed in claim 7, wherein the interleavingadjusts a memory size of an interleaver which performs the interleavingaccording to a data transmission rate.
 9. The data processing method asclaimed in claim 8, wherein the interleaver is a convolutionalinterleaver.
 10. The data processing method as claimed in claim 9,wherein a number of branches of the convolutional interleaver is set tobe a proper divisor of a transmission data unit of the digitalbroadcasting system.